WO2008098744A1

WO2008098744A1 - Punching tool, in particular slotting tool

Info

Publication number: WO2008098744A1
Application number: PCT/EP2008/001076
Authority: WO
Inventors: Hans Schäfer
Original assignee: Hartmetall-Werkzeugfabrik Paul Horn Gmbh
Priority date: 2007-02-17
Filing date: 2008-02-13
Publication date: 2008-08-21
Also published as: US20100104390A1; EP2125278A1; US8434972B2; EP2125278B1; DK2125278T3; PL2125278T3; ATE511936T1; DE102007008081A1; ES2366005T3

Abstract

A punching tool, in particular a slotting tool, comprising a holder (1) that defines a longitudinal axis (4) and has a shank (5) extending in the longitudinal direction as a carrier for a cutting body (31, 33), which can be fixed in a seat of the shank (5) by means of a clamping device (51), is characterized in that the seat has a passage that is at a distance from the free end (7) of the shank (5), extends transversely in relation to the longitudinal axis (4) and the inner side of which forms guiding surfaces for abutting surfaces of the cutting body (31, 33) that can be pushed into the passage in the direction of insertion, wherein an end position limitation for the pushed-in cutting body (31, 33) is formed on guiding surfaces and on associated abutting surfaces and the clamping device (51) on the cutting body (31, 33) produces a force component pressing the latter against the end position limitation.

Description

Carbide tool factory Paul Hörn GmbH, under the wood 33-35,

72072 Tübingen

Impact tool, in particular grooving tool

The invention relates to an impact tool, in particular grooved impact tool, having a longitudinal axis defining a holder having a longitudinally extending shaft as a support for a cutting body, which is fixed in a seat of the shaft by means of a clamping device.

When such impact tools are to be used for machining operations where the highest accuracy and high surface quality are required, two main requirements must be met. First, it must be ensured by a high strength of the shaft that forces and moments, in particular bending moments, which are introduced via the cutting body in the seat, are taken absolutely safe from the shaft, without resulting in changes in geometry. Second, the positional fixation of the cutting body itself must be designed absolutely secure even in the seat of the shaft.

Both of these requirements are not readily met, especially when the impact tool, especially when used as a grooving tool, is provided for internal machining in a bore of a workpiece or in a hollow body in order to achieve a sufficient working depth in these cases, for example to inner Longitudinal grooves in one Bore with sufficient groove length, it is necessary that the shaft has a corresponding length. If the machining is to be carried out in relatively small diameter bores, the shaft will inevitably have a slender, elongated shape, which is detrimental to structural strength. To this problem is added that the formation of the seat for the cutting body causes a local reduction of the supporting material cross-section of the shaft, which also affects the structural strength.

In view of this problem, the invention has the object to provide an impact tool, in particular grooved impact tool, in which a particularly torsional and rigid working position of the cutting body is ensured even with a comparatively slender design of the shaft.

According to the invention, this object is achieved by an impact tool having the features of claim 1 in its entirety.

Characterized in that according to the characterizing part of claim 1, the seat of the cutting tool is formed by a passage in the shaft, which forms a guide for the cutting body to be inserted into the passage, wherein guide surfaces of the passage bear against contact surfaces of the cutting body, the cutting body is suitable in the passage chambered and thereby forms a reinforcing body, which compensates for the conditional by the formation of the passage reduction of the material cross-section of the shaft so to speak. Due to the fact that, according to the invention, an end position limitation is also provided for the inserted cutting body and the clamping device is designed such that it generates a force component on the cutting body which presses it against the end position limitation, this results in optimum positional fixing of the cutting body by the abutment of its contact surfaces against the cutting body Guide surfaces of the passage in which the cutting body is chambered.

With regard to the formation of the limit stop, the arrangement may be such that at least one of a contact surface projecting surface portion is provided on the cutting body, which forms a stop surface which comes when inserting the cutting body to rest on a counter stop forming a shoulder surface of the passage.

In alternative embodiments, however, the arrangement can also be made such that at least one surface part of the guide surface of the passage forms an inclined surface inclined with respect to the insertion direction, against which a chamfer of the cutting body forming part of the contact surface engages when inserting the cutting body, if this is inserted into the desired end position.

Regardless of the design of the end position limitation, the fact that the clamping device generates a force component on the cutting body during clamping of the cutting body, which presses it against the end position limitation, ensures that the positional adjustment and fixing of the cutting element take place with maximum accuracy.

In advantageous exemplary embodiments, the cutting body has a main body to be accommodated in the passage of the shank in the form of a plate, whose opposite broad sides form contact surfaces for the guide surfaces of the passage. By such a large-scale system on the inside of the passage, the main body of the cutting body contributes in a special way to reinforcing the structure of the shaft. Advantageously, in such embodiments, the clamping device having a clamping screw which passes through a bore in the main body of the cutting body which extends perpendicular to its parallel sides defining broad sides, wherein provided for the clamping screw on the shaft a threaded bore in one of the guide surfaces of the passage is. This design opens up the advantageous possibility of structurally simple realization of the desired force component for application to the end position limitation on the cutting body by the relative position arrangements of the bore in the base body of the cutting body, the threaded bore in the passage of the shank and the limit stop for the cutting body are selected such that the tightening of the clamping screw produces both a clamping force and the force component acting in the insertion direction, the desired pressing of the projecting surface portion of the Schneidkör- pers to the counter-stop of the passage or the pressing of the bevel of the cutting body to the inclined surface of the passage of the shaft causes.

Preferably, the cutting body has at least one cutting edge on a with respect to the longitudinal axis radially extending extension of the base body.

In particularly advantageous embodiments, which allow a particularly efficient and economical production of longitudinal grooves in holes are to form two cutting edges, which extend diametrically diametrically from the shaft radially projecting and are impactingly effective in opposite directions, on the main body two to each other provided opposite extensions. In this case, the arrangement can be made such that the extensions are designed to be axially symmetrical to each other, preferably symmetrically to the axis of the bore, which is provided in the base body for the clamping screw.

The invention also relates to a cutting body for use in a push tool according to the invention, wherein the cutting body has the features specified in claim 11 or in claim 12 features.

The invention with reference to embodiments shown in the drawings will be explained in detail. Show it:

Fig. 1 is a perspective oblique view of an embodiment of the impact tool according to the invention, compared to a practical embodiment shown almost twice the scale; FIG. 2 is a perspective oblique view of a cutting body for the embodiment of FIG. 1 drawn on an even larger scale compared to FIG. 1; FIG.

Fig. 3 is a drawn approximately in the scale of Figure 1 side view of the embodiment. FIG. 4 shows a longitudinal section along the section line IV - IV of FIG. 3; FIG. Fig. 5 is a longitudinal section corresponding to Figure 4 of a second embodiment of the impact tool, wherein in a broken view, only the front part of the shaft is shown. Fig. 6 is a side view similar to FIG. 3 of both the first and the second embodiment, but with respect to FIG. 3 by 90

Degree twisted and wherein the shaft is located within the bore to be machined of a schematically indicated workpiece; Fig. 7 shows a comparison with Figure 6 about 1 16-fold enlarged drawn section corresponding to the section line VII-VII of Figure 6, wherein the workpiece is not shown. 8 and 9 are a front view and side view of the cutting body of the first embodiment shown in perspective in Figure 2, compared to a practical embodiment, drawn approximately in 3 / 2x magnification. 10 is a front view corresponding to FIG. 8 of the cutting body for the second embodiment of the impact tool, and FIG. 11 is a plan view of the cutting body of the first embodiment shown in approximately 8 times magnification compared to a practical embodiment.

The designated in Fig. 1 and 3 as a whole with 1 holder has a rear clamping part 3, with which the impact tool is clamped in a machine tool, not shown, by means of which the tool in the direction of the tool longitudinal axis 4 (Fig. 3 and 6) for a going forward thrust processing and a forthcoming shock processing in the reverse direction is movable. The clamping part 3 is adjoined by a shaft 5, which is tapered relative to the clamping part 3 and whose front shaft end is denoted by 7. While the clamping part 3 is circularly cylindrical in shape, the outer surface of the shaft 5 has a contour with flat surface areas 9 and 11, see in particular FIG. 1. At a small distance from the front end 7, the shaft 5 has a passage 13 whose inside Guide surfaces for a insertable in an insertion cutting body, which is denoted in the figures as a whole by 15 form. Further details of the cutter body 15 are illustrated in particular in FIGS. 8 to 11. The passage 13 has inner guide surfaces 17 in planes parallel to one another and with respect to the longitudinal axis 4 and guide surfaces 19 in planes extending transversely to the longitudinal axis 4. In cooperation with abutment surfaces of the cutting body 15 to be inserted, these guide surfaces 17 and 19 form a suitable guide, into which the cutting body 15 can be inserted in an insertion direction, from an input end of the passage 13, which is shown in Figs. 1, 3 and 4 and 5 as the upper end of the passage 13, where the passage is extended by inclined surfaces 21 and 23. From the insertion end of the cutting body 15 can be inserted into an end position, which is defined by an end position limitation and in which the guide surfaces 17 and 19 abut fittingly on the associated contact surfaces of the cutting body 15.

As mentioned, FIGS. 8 to 11 show further details of the cutting body 15, wherein FIGS. 8, 9 and 11 show a cutting body 15 for a first embodiment and FIG. 10 show a cutting body 15 for a second embodiment. In both embodiments, the cutting body 15 has a plate-like base body 25, whose broad sides 27 extend in mutually parallel planes. These broad sides 27 form with surface areas the contact surfaces for the guide surfaces 17 of the passage 13. The generally rectangular base body 25 forms with its planar, mutually parallel narrow sides 29, the contact surfaces for the guide surfaces 19 in the passage thirteenth

The cutting bodies 15 of both exemplary embodiments have projections 31 on two diametrically opposite corner regions of the main body 25, which are formed axially symmetrical to one another and each form a cutting edge 33. As can be seen most clearly from Fig. 8, the projections 31 are symmetrical to the axis of a through hole 35 which is located in the center of the broad sides 27 of the body 25 and at a bore end has a conical enlargement 37.

As already mentioned, the cutting body 15 can be inserted from the insertion end of the passage 13 into the guide in an insertion direction, in which guide surfaces 17, 19 are guided on the contact surfaces formed by the broad sides 27 and the narrow sides 29 of the cutting body, namely towards an end position limitation. The first and the second here writing embodiment differ only in terms of the formation of Endlagenbegrenzung. As shown in Fig. 7, in the first embodiment for this purpose in the passage 13, an extension 38 is provided through which a shoulder 39 is formed on the guide surface 17. This shoulder 39 forms a counter-abutment for a stop surface which is formed on the main body 25 of the cutting body 15. The relevant design on the base body 25 is best seen in FIGS. 4, 8 and in particular 11. As shown there, rises from the one broad side 27 of the body 25, a bump 41, which forms a bounded on three sides by bevels 43 plateau with a perpendicular thereto, located on the fourth side abutment surface 45 which at the end position of the cutting body 15 in Passage 13 cooperates with the counter-stop forming paragraph 39 in the passage 13.

As already mentioned, the main body 25 of the cutting body has a central bore 35 with end-side conical enlargement 37. As part of the clamping device, this bore 35 is penetrated by a clamping screw 47, which can be screwed into an opening on the guide surface 17 of the passage 13 threaded bore 49. The clamping screw 47 has in the manner of a countersunk seh rob a from the

Screw shank conically widening screw head 51 on. As best seen in Fig. 7 can be seen, in which the cutting body 15 is shown in its end position, the threaded bore 49 and the through hole 35 in the main body 25 of the cutting body 15 are such eccentric to each other that when tightening the clamping screw 47 of the conical head 51 in cooperation with the conical Enderweiterung 37 of the bore 35 generates a force component on the cutting body 15, which urges it in viewing direction as shown in FIG. 7 down. This means that the clamping screw 47 not only clamps the cutting body 15 by pressing the broad side 27 of the main body 25 against the guide surface 17 of the passage 13, but that the clamping piece 47 on the bump 41 of the cutting body pers 15 trained stop surface 45 is pressed for the defined Endlagenbegrenzung to the paragraph 39 in the passage 13.

As the comparison of FIGS. 8 and 10 shows, the cutting body 15 of the second embodiment has no bump 41 on the base body 25. Instead, to form the end position limit, the narrow side 29 of the main body 25 located at the bottom in FIG. 10 has an inclination with respect to the other narrow side 29, which is approximately on the order of 11 angular degrees in the exemplary embodiment shown. In a corresponding manner, as shown in Fig. 5, the associated guide surface 19 of the passage 13 is provided with a corresponding inclination. While in the first embodiment, the passage 13 on that guide surface 17 which is provided with the passage opening 53 for the clamping screw 47, a paragraph 39 forming extension 38 as a counter stop for the bump 41 of the cutting body, in the second embodiment, this guide surface 17th , except for the opening 53, continuously. In the same way as in the first embodiment, however, the threaded bore 49 and the bore 35 in the main body 25 of the cutting body 15 are so eccentric in the second embodiment that when tightening the clamping screw 47, the conical surface on the head 51 in cooperation with the conical extension 37 of the bore 35 generates a force component on the cutting body 15 along the guide surfaces 17, such that at the end position the oblique narrow side 29 of the base 25 and the inclined guide surface 19 of the passage 13 abut each other, whereby the Einschiebebewegung by the resulting constriction of the guide in the final position is limited.

Due to the fact that, in both exemplary embodiments, mutually symmetrical projections 31 with cutting edges 33 are provided on the main body 25 of the cutting body, the tool according to the invention is particularly In order to produce, as it were, "continuous" machining, a plurality of longitudinal grooves 55 in the bore 57 of a workpiece 59, which is only schematically indicated in Fig. 6. The symmetrical arrangement of the projections 31 with the cutting edges 33, the tool acts on going working movement and abutting a working movement, so that in a work cycle, in which a relative and forthcoming movement between holder 1 and workpiece 59 is generated, for example by the holder being driven longitudinally, two opposing grooves 55 can be machined either advancing movements mediated by the workpiece 59 or by advancing the holder 1. In order to produce grooves 55 distributed on the inner circumference of the respective bore 57, the workpiece 59 may be rotated relative to the holder 1 or rotated relative to the workpiece 59.

Claims

Patent claims

1. impact tool, in particular grooving tool, with a longitudinal axis (4) defining a holder (1) having a longitudinally extending shank (5) as a support for a cutting body (15) in a seat of the shank (5 ) is fixable by means of a clamping device (47), characterized in that the seat has a distance from the free end (7) of the shank (5) having a transversely to the longitudinal axis (4) extending passage (13) whose inner side te Guide surfaces (17, 19) for contact surfaces (27, 29) of the in

Passage (13) insertable in an insertion cutting body (15), wherein on guide surfaces (17, 19) and on associated contact surfaces (27, 29) an end position limit for the inserted cutting body (15) is formed and the clamping device (47) on the cutting body (15) one pushing it to the end position limit

Force component generated.

2. impact tool according to claim 1, characterized in that for forming the Endlagenbegrenzung on the cutting body (15) at least one of a contact surface (27) projecting surface portion (41, 43) is provided which forms a stop surface (45) which during insertion of the Cutting body (15) for engagement with a counter stop forming a step (39) of a guide surface (17) of the passage (13) comes.

3. impact tool according to claim 1, characterized in that for forming the Endlagenbegrenzung at least a surface part of the guide surface (17) of the passage (13) forms an inclined to the insertion inclined surface, at the time of insertion of the cutting body (15) a part of the contact surfaces (29) forming bevel of the cutting body (15) is applied.

4. Impact tool according to one of claims 1 to 3, characterized in that the cutting body (15) in the passage (13) of the shank (5) to be accommodated base body (25) in the form of a plate whose opposite broad sides (27) Anlageflä - Chen for the guide surfaces (17) of the passage (13) form.

5. Impact tool according to claim 4, characterized in that the clamping device has a clamping screw (47) which in the base body (25) of the cutting body (15) passes through a bore (35) which is perpendicular to its parallel sides defining broad sides (27) runs, and that for the clamping screw (47) on the shaft (5) has a threaded bore (49) in one of the guide surfaces (17) of the passage (13) is provided.

6. impact tool according to claim 5, characterized in that the relative position arrangements of the bore (35) in the base body (25) of the cutting body (15), the threaded bore (49) in the passage (13) of the shank (5) and the Endlagenbegrenzung for Cutting body (15) are selected such that at this when tightening the Klemmschrau- be (47) the force component for pressing the stop surface (45) of the cutting body (15) to the counter-stop (39) of the passage (13) or the chamfer of Cutting body (15) is produced on the inclined surface of the passage (13) of the shaft (5).

7. Impact tool according to one of claims 4 to 6, characterized in that the cutting body (15) has at least one cutting edge (33) on a relative to the longitudinal axis (4) radially extending projection (31) of the base body (25).

8. impact tool according to claim 7, characterized in that for forming two cutting edges (33), which, diametrically to each other, from Shaft (5) extend radially projecting and are impactingly effective in opposite working directions, on the base body (25) has two mutually opposite extensions (31) are provided.

9. impact tool according to claim 8, characterized in that the extensions (31) are designed to be axially symmetrical to each other.

10. Impact tool according to claim 9, characterized in that the extensions (31) to the axis of the bore (35) of the base body (25) are symmetrical.

11. Cutting body for a push tool according to one of claims 1 to 10, with a plate-like base body (25) having at least one cutting edge (33) forming an extension (31) and having a on a broad side (27) of the plate-like base body (25 ) projecting cusp (41) having a step (45) which forms a stop surface for a counter-stop (39) in the seat (13) of the tool holder (1).

12. Cutting body for an impact tool according to one of claims 1 to 10, comprising a plate-like base body (25) having at least one cutting edge (33) forming an extension (31) and on a narrow side (19) has an inclined surface, which for the End position positioning on a in the seat (13) of the tool holder (1) formed inclined surface (19) can be applied.

13. Cutting body according to claim 11 or 12, characterized in that the base body (25) has two diametrically arranged extensions (31) each having a cutting edge (33) are provided.

14. Cutting body according to one of claims 11 to 13, characterized in that it consists of a hard metal material.